The present invention relates to cutting inserts, cutting tools and cutting methods using the same.
A cutting tool for machining a work made of metals and the like comprises a holder and a cutting insert attached to the holder.
The cutting insert disclosed in Patent Document 1 comprises a corner edge that is located between two sides constituting an upper surface thereof, and a first breaker wall and a second breaker wall on the inner side thereof. The first breaker wall is disposed in the vicinity of the corner edge, and is inclined upward as approaching inward from the corner edge. The second breaker wall is located inward and upward with respect to the first breaker wall, and is inclined upward as approaching inward from the corner edge.
In addition, a first flat surface is provided between the first breaker wall and the second breaker wall. The intersection portion of the first breaker wall and the first flat surface is inclined upward as it moves away from the corner edge.
Patent Document 1: Japanese Patent Laid Open Publication No. 2006-110666.
However, when the above-described cutting insert generates chips under cutting conditions having a large cutting depth (high cut machining), there is a concern that chips has a roughly high cutting resistance at a position far away from the corner section since the chips come in contact with the first breaker wall with great force even at a position far away from the corner edge. Furthermore, there is another concern that the chips are not curled in a stable manner under cutting conditions having a large cutting depth and are clogged between the cutting edge that is located on the side adjacent to a corner edge, or the corner edge, and a projecting section of the first and the second breaker walls.